The modelling of complex technological systems serves as the foundation for enhancing process performance, including sustainability features (triple-bottom line). The European Green Deal, proposed in 2019, aims to cut greenhouse gas emissions by 2050 and foster a resource-independent economy. Such a change must be carefully planned. Comprehensive sustainability protocols and guidelines are necessary to describe the standardized methodological procedure, the environmental certification procedures that allow market comparability and identification of the best solutions, the databases, the calculation tools and software, and the benchmark and target with which to make comparison. Policies and regulatory or incentive instruments promote the broad adoption of these approaches and ensure that policies reduce environmental, economic, and social impacts. This paper consists in an overview of sustainability assessment tools’ role in energy policy and short- and long-term modeling of more eco-friendly energy-product systems. Additionally, the paper explores these methods’ pros and cons in planning, analyzing, and optimizing energy/product systems, also according to the circular economy paradigm. All of these strategies aim to help the decision-maker make more consistent judgments by taking into consideration essential objective, such as end user or stakeholder demands, and minimizing subjective elements. An extensive listing of Sustainability accreditation and communication tools is provided. Sustainability assessment is an evaluation and optimization method that promotes sustainable development in all political planning and decision-making. It examines the social, economic, and environmental effects, finds conflicting goals, and recommends early optimization. Potentially, sustainability assessment should be integrated into the political planning process and depend on domain-specific research and assessments that currently exist or are planned, such as in combination with decision-making. Sustainability assessment is not designed to be an extra analytical tool. A sector-specific environmental or economic study from a strategic environmental analysis or regulatory effect analysis may be crucial to a sustainability assessment.

As a promising pollutant emission reduction technology, biomass mixed combustion has attracted widespread attention worldwide. This paper aimed to study the characteristics of biomass mixed combustion and temperature distribution. A combination of simulation and experimental methods was adopted. The results showed when four kinds of biomass were burned separately, their highest temperatures in the center section of combustion chamber were corn stalk>cotton stalk>sawdust>rice straw in descending order. Compared with other three biomass, the highest temperature of corn stalk was more than 100 K higher, which mainly occurred during the full combustion stage, mainly because corn stalk had high volatile content and caught fire easily. In addition, with the optimal mixed combustion parameters, biomass mixed combustion improved the combustion characteristics of single biomass combustion. The optimal blending ratio of corn stalk to rice straw was 7:3, and the optimal primary air velocity and temperature were 48 m/s and 1300 K, respectively. With the optimal blending ratio, the maximum temperature in the center section was higher than that of single biomass combustion, with advanced ignition point, relatively uniform temperature distribution in the combustion chamber and good combustion performance, because the precipitation and combustion of high volatile components during mixed combustion caused the surface temperature of fixed carbon to rise rapidly to reach the ignition temperature. Finally, this paper studied the combustion characteristics of corn stalk and rice straw with the optimal mixed combustion parameters in mixed combustion experiment, and verified the good consistency between the simulation and experimental values. Therefore, biomass mixed combustion technology provides an important reference for solving the problem of low calorific value of single biomass combustion.